In Blender 2.8, how to make an animation with different objects appear at different keyframes
If I understand your question correctly you're simply trying to switch objects visible for one frame, then off again to be replaced by the next object at the next frame and so on...

The slo-mo video below shows masks 10, 11, &amp; 12 being visually switched in and out at frames 10, 11 &amp; 12 respectively.  This is done in the Outliner at right.  The eye icon is simply keyframed on or off by hovering over the icon, clicking so it's on or off, then pressing  "i" key. (insert keyframe)  If you make a mistake, hover on it again and press  "ALT-i"  to remove the keyframe, or CTL-Z.

Note - when not rendering  in OpenGL, the camera icons would need to be switched and keyframed the same way.